Metropolitana Linea 1 Capodichino

The central element of the design of Capodichino station is the roof. The design utilises complex geometry based on a ‘toroid’ 3D shape with 46 main radial ribs. These ribs spring from the top of the station shaft and each has a diameter of 33m across the inside faces. The maximum length of one rib is 39m and the area of the main canopy is 4,700m². The ribs are interconnected by diagonal struts which stiffen the structure. The sizes of these sections vary to suit their internal forces.

A ‘belt’ tie follows the outer perimeter of the canopy. This provides additional rigidity to the canopy and limits vertical deflections by preventing ‘spread’ of the roof. The belt tie is likely to be pulled inwards so that the ribs and louvres feather outwards towards the rim. The main structure is clad with aluminium louvres. These are arranged in a ‘ridge-and-valley’ formation around the roof to assist with drainage. At the present stage of the design, the main ribs have been modelled as steel box sections.

The design has been developed – using computer-based 3D geometric modelling – to minimise the number of elements which need to be fabricated for the structure. This, in turn, will simplify the construction process and, ultimately, ensure cost effectiveness.

Timber and steel have been used throughout in the construction of the roof structure above ground. However, to ensure that the design complies with local fire and other safety regulations, the structure underground is made of concrete.

Whilst security issues have clearly been a key factor affecting this project, the design of the roof is still expressed in the form of the structure used below-ground and, in spite of the difference of materials, the above- and below-ground elements produce a near-continuous structure.

Inside the station building, the escalator layout has been designed to maximise passenger throughput and flows, although the design also reflects a response to key safety and security issues, and the need to ensure that passengers can evacuate the station easily and rapidly in the event of a safety threat arising. The escalators effectively form an underground ‘spine’ to the station and are designed to ensure that there is no cross-flow of passengers entering or leaving.Key points

City & Context

Metropolitana Linea 1 has been designed to connect all transport types across Naples by offering a series of ‘hubs’ along the route allowing passengers to change for rail, airline, bus and ferry services at different stations. This, in turn, will help to reduce reliance on car journeys and encourage more people in the city to use public transport.

Legibility

The roof design is mirrored at ground level to provide on-the-ground route-finding for passengers entering and leaving the station.